The flow-field of dynamic gas lock (DGL) of single-component purge gas is simulated with the type and flux of purge gas and the outgassing rate of dirty gases as variables, and that of multi-component purge gas is also simulated with the volume ratio of mixed purge gases as variable. The simulation results indicate that, for single-component purge gas, the suppression ratio of DGL increases with the increment of gas flux and molecular weight, but has no relation to the outgassing rate of dirty gas. As for the multi-component purge gas, the suppression ratio of DGL approximately remains constant with the increment of volume fraction of the purge gas with large molecular weight. As for the practical application in engineering, it is recommended to use argon-hydrogen mixture as the purge gas in DGL. When the purge gas flux reaches 6.5 Pa·m3·s-1, nearly 25% of the purge gas flows into wafer-stage chamber and the suppression ratio of DGL is more or less 75%. This simulation result provides a basis for the development of DGL in extreme ultraviolet lithography.